Methods for the analysis of fermentation products have been developed which allow the separation and quantitation of all of the constituents in concentrated mixtures and most of the spectrum of fermentation products in small dilute samples. Phenacyl derivatives of the major acid fermentation products have been made and quantitated by gas chromatography using a capillary column. Extracts of samples obtained from animals and samples obtained from discrete sites from humans have been analyzed by these methods and the expected array of fermentation products quantitated. These analyses are being applied to samples obtained from exposed cemental surfaces and from cemental surfaces with carious lesions. Fermentation products have also been separated on a macro scale using an HPLC column and all expected fermentation products are separable and may be collected and identified for proposed tracer experiments. Extractable adenosine triphosphate (ATP) has been analyzed in dental plaque samples and a variety of pure cultures of plaque bacteria using commercial extracting and luciferase reagents. The limitations and feasibility for the use of these reagents for the study of dental plaque has been examined.